Distribution and the evolutionary history of G-protein components in plant and algal lineages
Distribution and the evolutionary history of G-protein components in plant and algal lineages
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G蛋白成分在植物和藻类谱系中的分布和进化历史
DOI：
10.1093/plphys/kiac153
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发表时间：
2022
期刊：
影响因子：
7.4
通讯作者：
Pandey, Sona
中科院分区：
文献类型：
--
作者：
Mohanasundaram, Boominathan;Dodds, Audrey;Kukshal, Vandna;Jez, Joseph M.;Pandey, Sona
由Gα-、Gβ-和Gγ-亚基组成的异源三聚体G蛋白复合物和G蛋白信号转导调节因子（RGS）在大多数真核细胞谱系中是保守的。由这些蛋白质介导的信号通路影响整体生长、发育和生理。在植物中，这种蛋白质复合物的特征主要来自被子植物，除了展叶土藓（立碗藓）和轮藻（轮藻）。即使在被子植物中，特定的G蛋白组分在某些物种中缺失，而独特的植物特异性变体-超大Gα（XLGα）和富含半胱氨酸的Gγ蛋白-也存在。G蛋白的分布和进化历史及其在非被子植物谱系中的功能仍然是未知的。我们使用大量可用的序列数据来探索这一点，这些数据涵盖了藻类到被子植物，代表了大约15亿年前分化的现存物种，使用BLAST，同线性分析和定制的隐马尔可夫模型轮廓搜索。我们表明，一个最小的一组组成部分，形成XLGαβγ三聚体存在于整个陆地植物谱系，但它们的存在是零星的藻类。此外，单个组件具有不同的进化历史。XLGα表现出许多谱系特异性基因重复，而Gα和RGS则表现出几种基因丢失的情况。类似地，Gβ在数量和结构上都保持不变，但Gγ在陆地植物出现之前发生了分化，并经历了蛋白质结构域的变化，这导致了三种不同的亚型。这些结果突出了进化上的奇异性，并总结了这种保守的信号通路在植物中的系统模式。他们还提供了一个框架，制定有关问题的植物G蛋白信号在进化的背景下。
Heterotrimeric G-protein complexes comprising Gα-, Gβ-, and Gγ-subunits and the regulator of G-protein signaling (RGS) are conserved across most eukaryotic lineages. Signaling pathways mediated by these proteins influence overall growth, development, and physiology. In plants, this protein complex has been characterized primarily from angiosperms with the exception of spreading-leaved earth moss (Physcomitrium patens) andChara braunii(charophytic algae). Even within angiosperms, specific G-protein components are missing in certain species, whereas unique plant-specific variants—the extra-large Gα (XLGα) and the cysteine-rich Gγ proteins—also exist. The distribution and evolutionary history of G-proteins and their function in nonangiosperm lineages remain mostly unknown. We explored this using the wealth of available sequence data spanning algae to angiosperms representing extant species that diverged approximately 1,500 million years ago, using BLAST, synteny analysis, and custom-built Hidden Markov Model profile searches. We show that a minimal set of components forming the XLGαβγ trimer exists in the entire land plant lineage, but their presence is sporadic in algae. Additionally, individual components have distinct evolutionary histories. The XLGα exhibits many lineage-specific gene duplications, whereas Gα and RGS show several instances of gene loss. Similarly, Gβ remained constant in both number and structure, but Gγ diverged before the emergence of land plants and underwent changes in protein domains, which led to three distinct subtypes. These results highlight the evolutionary oddities and summarize the phyletic patterns of this conserved signaling pathway in plants. They also provide a framework to formulate pertinent questions on plant G-protein signaling within an evolutionary context.